Plot in a tabbed MDI window briefly shows coarse image

[allenbarnett5]

Hi: My application uses the TabbedView QMdiArea interface. I've noticed that when I switch between tabs which show JKQTPlotter plots that there is a brief image of a very coarse rendition of the plot before it draws the plot at the correct resoution. This appears to be because QMdiArea sets the window that's being hidden back to its un-maximized size (i.e., it calls showNormal on the widget). Therefore, when you show it again, JKQTPlotter has to draw it at the maximized size again. I was wondering if there is a way to defer the rendering until the window size settles down? I tried setting the delayed resize time to 1 second, but that only seemed to prolong the coarse view for 1 second. Most likely I don't know what I'm doing :-)

Below is the smallest program I could think of to reproduce the issue. If you click "Button 1" it will open a new tab with a plot and there will be a brief image of a coarse version of the plot. If you switch between a couple of plot windows, you can see the resize effect.

I've tested this on linux and windows with Qt 6.9.3 and JKQTPlotter 5.0.0.

I'd appreciate any kind of guidance to reduce the effect.

Thanks,
Allen

#include <QApplication>
#include <QMdiArea>
#include <QPushButton>
#include <QResizeEvent>
#include <jkqtplotter/jkqtplotter.h>
#include <jkqtplotter/graphs/jkqtplines.h>

class MyPlotter : public JKQTPlotter
{
public:
protected:
  void resizeEvent ( QResizeEvent* event )
  {
    qDebug() << "resize" << event;
    JKQTPlotter::resizeEvent( event );
  }
};

int main ( int argc, char* argv[] )
{
  QApplication app( argc, argv );
  QMdiArea ma;
  ma.setViewMode( QMdiArea::TabbedView );
  ma.show();
  QPushButton pb1( "Button 1" );
  ma.addSubWindow( &pb1 );
  pb1.show();
  QObject::connect( &pb1, &QPushButton::clicked,
                    [&ma]() {
                      auto plotter{new MyPlotter/*JKQTPlotter*/};
                      auto ds{ plotter->getDatastore() };
                      auto x{ ds->addCopiedColumn( QList<double>{0,1}, "x" ) };
                      auto y{ ds->addCopiedColumn( QList<double>{0,1}, "y" ) };
                      auto g{ new JKQTPXYLineGraph(plotter) };
                      g->setXColumn( x );
                      g->setYColumn( y );
                      plotter->addGraph( g );
                      plotter->setMinimumSize( 300, 300 );
                      ma.addSubWindow( plotter );
                      plotter->show();
                    } );
  ma.resize( 800, 800 );
  app.exec();
  return 0;
}